The present invention relates to a high definition CRT display having an automatic correction device for horizontal deflection distortions and particularly relates to such a device suitable for use in a multiple scanning type display.
In order to correct horizontal deflection distortions, prior art CRT displays, as described in D. G. Fink, "Television Engineering Handbook", McGraw-Hill, 1957, pp. 15-20, use a horizontal linearity coil utilizing a saturable reactor and an S-shaped capacitor connected in series with the horizontal deflection coil as means for achieving the correction.
The prior art correction means have exhibited good performance when applied to ordinary television receivers, but there arise problems with it when applied to modern high definition display in that its correcting accuracy is insufficient and, in particular, a distortion is generated thereby dependent on the ambient temperature. Further, the prior art correction means when applied to the multiple scanning type display, in which the display must support a plurality of signal sources whose horizontal scanning frequencies are different from one another, the deflection distortion greatly varies with the input horizontal frequency.